explosion minor rework + fix (#21718)

Content.Shared/Damage/Systems/DamageableSystem.cs

@@ -1,7 +1,9 @@
 using System.Linq;
+using Content.Shared.Administration.Logs;
 using Content.Shared.Damage.Prototypes;
 using Content.Shared.FixedPoint;
 using Content.Shared.Inventory;
+using Content.Shared.Mind.Components;
 using Content.Shared.Mobs.Components;
 using Content.Shared.Mobs.Systems;
 using Content.Shared.Radiation.Events;
@@ -16,12 +18,14 @@ namespace Content.Shared.Damage
     public sealed class DamageableSystem : EntitySystem
     {
         [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
+        [Dependency] private readonly ISharedAdminLogManager _adminLogger = default!;
         [Dependency] private readonly SharedAppearanceSystem _appearance = default!;
         [Dependency] private readonly INetManager _netMan = default!;
         [Dependency] private readonly MobThresholdSystem _mobThreshold = default!;
 
         private EntityQuery<AppearanceComponent> _appearanceQuery;
         private EntityQuery<DamageableComponent> _damageableQuery;
+        private EntityQuery<MindContainerComponent> _mindContainerQuery;
 
         public override void Initialize()
         {
@@ -33,6 +37,7 @@ namespace Content.Shared.Damage
 
             _appearanceQuery = GetEntityQuery<AppearanceComponent>();
             _damageableQuery = GetEntityQuery<DamageableComponent>();
+            _mindContainerQuery = GetEntityQuery<MindContainerComponent>();
         }
 
         /// <summary>

Content.Shared/Explosion/ExplosionEvents.cs

@@ -1,6 +1,5 @@
+using Content.Shared.Damage;
 using Content.Shared.Inventory;
-using Robust.Shared.Map;
-using Robust.Shared.Serialization;
 
 namespace Content.Shared.Explosion;
 
@@ -20,3 +19,34 @@ public record struct GetExplosionResistanceEvent(string ExplosionPrototype) : II
 
     SlotFlags IInventoryRelayEvent.TargetSlots =>  ~SlotFlags.POCKET;
 }
+
+/// <summary>
+/// This event is raised directed at an entity that is about to receive damage from an explosion. It can be used to
+/// recursively add contained/child entities that should also receive damage. E.g., entities in a player's inventory
+/// or backpack. This event will be raised recursively so a matchbox in a backpack in a player's inventory
+/// will also receive this event.
+/// </summary>
+[ByRefEvent]
+public record struct BeforeExplodeEvent(DamageSpecifier Damage, string Id, List<EntityUid> Contents)
+{
+    /// <summary>
+    /// The damage that will be received by this entity. Note that the entity's explosion resistance has already been
+    /// used to modify this damage.
+    /// </summary>
+    public readonly DamageSpecifier Damage = Damage;
+
+    /// <summary>
+    /// ID of the explosion prototype.
+    /// </summary>
+    public readonly string Id = Id;
+
+    /// <summary>
+    /// Damage multiplier for modifying the damage that will get dealt to contained entities.
+    /// </summary>
+    public float DamageCoefficient = 1;
+
+    /// <summary>
+    /// Contained/child entities that should receive recursive explosion damage.
+    /// </summary>
+    public readonly List<EntityUid> Contents = Contents;
+}

Content.Shared/Storage/Components/SharedEntityStorageComponent.cs

@@ -124,6 +124,12 @@ public abstract partial class SharedEntityStorageComponent : Component
     /// </summary>
     [ViewVariables]
     public Container Contents = default!;
+
+    /// <summary>
+    /// Multiplier for explosion damage that gets applied to contained entities.
+    /// </summary>
+    [DataField]
+    public float ExplosionDamageCoefficient = 1;
 }
 
 [Serializable, NetSerializable]